The present invention relates to an molded product of polyarylene thioether (hereinafter referred to as PATE) crystallized and having a high elongation.
More in detail, the present invention relates to an molded product which has been produced by curing a substantially linear PATE having a melt viscosity (hereinafter means the value measured at 310.degree. C. and a shearing rate of 200 second.sup.-1) of 1,000 to 15,000 poises, thereby converting the PATE into a PATE resin showing the melt viscosity of 5,000 to 16,000 poises and a non-Newtonian coefficient, n, of 1.5 to 2.1, melt-extruding the cured PATE resin, taking-off the extruded PATE resin at R.sub.1 (hereinafter defined as the ratio of a taking-off speed to an extruding speed at the nozzle of a melt extruded product) of 10 to 1,000 and then crystallizing the taken-off material until its crystallization degree (hereinafter defined as the value measured by a density method) reaches not less than 20 wt%.
Further, the present invention relates to a use of the molded PATE product, namely, a coated electric wire having the molded product as a coating layer.
Hitherto, PATE represented by polyparaphenylene thioether is one of the engineering resins which are excellent in various physical properties such as heat-resistance, chemical resistance, flame resistance, moisture-resistance, rigidity, etc. Most of these physical properties are not expressed unless PATE is sufficiently crystallized. Accordingly, it is an extremely important matter to increase the crystallization degree of the molded product of PATE. However, when a molded product of PATE is sufficiently crystallized by a thermal fixing treatment, the elongation of the product is reduced sharply while the heat-resistance of the product is increased. Accordingly, there has been a problem that such a PATE is unsuitable for the heat-resistant coating of electric wires to which high elongation is required together with a heat-resistance.
The present inventors have extensively studied for obtaining a molded PATE resin product, which has a heat-resistance and a high elongation simultaneously. They have finally found that a molded product of PATE resin, which has a heat-resistance and a high elongation simultaneously, can be obtained by melt-extruding a PATE having appropriate viscosity and non-Newtonian coefficient, which is obtained by curing a substantially linear PATE and fluid-orienting the extruded product by taking-off the extruded PATE with appropriate speed, then highly crystallizing the extruded product by a thermal fixing treatment.
The present invention has been completed on the basis of those findings.